An object rolling down an inclined plane with a velocity of xm/s, then its acceleration is

Question

$\begin{array}{1 1} (a)\; \frac{x}{2} m/s^2 \\ (b)\; x^2 m/s^2 \\ (c)\; 2x m/s^2 \\ (d)\; 10 m/s^2 \end{array}$